Browning containers for microwave ovens at present available on the market include, as browning coating, a conducting film of tin oxide. They have a fairly limited lifespan. Depending on the use, the heating time is longer and longer. This deterioration of the heating characteristics is in relationship with the low resistance to detergents of the electrically conducting tin film. This tin oxide film is normally applied by a process including heating the support with a solution of a thermally decomposable tin compound. In addition, this tin oxide film is not flame resistant, which limits the use of this dish exclusively to microwave ovens.